Journey with Confidence RV GPS App RV Trip Planner RV LIFE Campground Reviews RV Maintenance Take a Speed Test Free 7 Day Trial ×

Thread Tools Search this Thread Display Modes
Old 07-28-2019, 05:11 PM   #1
2 Rivet Member
fluxcap's Avatar
1977 Argosy Minuet 6.0 Metre
Newnan , Georgia
Join Date: Jun 2015
Posts: 53
Are thetford valves “one-way”?

Sorry for what may be a dumb question, but do thetford valves only seal in one direction?

I installed a new valve in my black tank (1977 argosy minuet). It works great as far as holding back the “stuff” in the black tank. However, minuets don’t have a grey tank for the shower water. And as I drove home some of the leftover water in the shower plumbing sloshed it’s way to the termination cap, which was capped. And as it backed up to the backside of the black valve, it leaked out through the hole in the valve where the handle rod comes through.

After I noticed it, I did a test and put the termination cap back on and then poured about 2 gallons down the shower and it again backed up to the black valve and poured out through the handle hole.

Is this normal? Seems like if it’s that easy for water to slip out that hole, then there could possibly be leaks there when pulling the handle and dumping (though I didn’t experience any on this trip).

fluxcap is offline   Reply With Quote
Old 07-28-2019, 06:48 PM   #2
Half a Rivet Short
2017 30' Classic
2022 Interstate 24X
Carlisle , Pennsylvania
Join Date: May 2017
Posts: 14,937

The normal waste valves are "two way" in the sense you describe. When closed they will not let "stuff" out or in.

uncle_bob is online now   Reply With Quote
Old 07-28-2019, 06:58 PM   #3
2 Rivet Member
fluxcap's Avatar
1977 Argosy Minuet 6.0 Metre
Newnan , Georgia
Join Date: Jun 2015
Posts: 53
Thanks! I didn’t remember the old valve doing this, but wasn’t sure. I’m going to investigate it more on my next day off, and see if I can figure out why it’s happening. This simple valve replacement has been nothing but a headache, haha.
fluxcap is offline   Reply With Quote

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
Can old LP tank valves be upgraded to OPD valves? jimblacker LP Gas, Piping, Tanks & Regulators 8 03-26-2014 07:07 AM
Thetford Valves, Repair or replace? Gkiesel Waste Systems, Tanks & Totes 3 06-21-2007 12:41 PM
Thetford Valves? sugarloafin' Waste Systems, Tanks & Totes 7 06-15-2007 11:23 AM
Leaky Thetford toilet valves raebaker06 Sinks, Showers & Toilets 7 03-28-2007 08:12 PM
Valves and Valves smily Plumbing - Systems & Fixtures 5 08-22-2002 05:01 AM

Featured Campgrounds

Reviews provided by


This website is not affiliated with or endorsed by the Airstream, Inc. or any of its affiliates. Airstream is a registered trademark of Airstream Inc. All rights reserved. Airstream trademark used under license to Social Knowledge LLC.

All times are GMT -6. The time now is 07:21 AM.

Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2023, Jelsoft Enterprises Ltd.